from components.aplant import APlant
from components.plant import delay

class Pot(APlant):
	def __init__(self, dt):
		APlant.__init__(self)
		self.dt = dt

		self.e = 0
		self.x = 0
		self.p_pot = 0

		# Plant specific thermal capacity [W*s/(kg*K)], mass [kg], energy
		# loss coefficient [W/(kg*K)] and transport propagation delay [s]
		# - all None until set_plant_params() is called; process() checks
		# for that rather than silently computing on bogus values.
		self.C = None
		self.M = None
		self.L = None
		self.Td = None
		self.delay = None

		# Plant temperature [°C] - seeded from theta_amb the first time
		# set_ambient_temperature() is called (see there), or overridden
		# explicitly via initial(). None until either happens;
		# process() checks for that too.
		self.temp = None

		# Ambient temperature [°C] - None until set_ambient_temperature()
		# is called; process() checks for that as well.
		self.theta_amb = None

		# Set power [W]
		self.p_in = 0

	def set_plant_params(self, params):
		self.C = params['C']
		self.M = params['M']

		# Negative input power as a function of plant mass and
		# temperature difference T_plant and T_ambient:
		# P_loss = L * Mass * (T_plant - T_ambient)
		self.L = params['L']

		self.Td = params['Td']
		self.delay = delay.Delay(self.dt, self.Td, 0)

	def set_ambient_temperature(self, theta_amb):
		self.theta_amb = theta_amb
		# Only seeds the plant's own starting temperature the first time
		# this is called (i.e. there's no real temperature yet) - once a
		# run is in progress, changing the ambient setting must not
		# clobber whatever temperature has actually been simulated since.
		if self.temp is None:
			self.temp = theta_amb

	def initial(self, temp):
		self.temp = temp

	def activate(self, enable):
		pass

	def process(self):
		if self.delay is None:
			raise RuntimeError("Pot.process(): plant params not set - call set_plant_params() first")
		if self.theta_amb is None:
			raise RuntimeError("Pot.process(): ambient temperature not set - call set_ambient_temperature() first")

		self.delay.put(self.p_in)

		p_loss = self.L * self.M * (self.temp - self.theta_amb)
		self.p_pot = self.delay.get() - p_loss

		self.temp = min(100, self.temp + self.p_pot/(self.M * self.C) * self.dt)

	def is_activated(self):
		return True

	def set_thermal_params(self, M, C):
		self.M = M
		self.C = C

	def set_power(self, power):
		self.p_in = power

	def get_power(self):
		return round(self.p_in, 1)

	def get_temperature(self):
		return self.temp

	def get_p_pot(self):
		return self.p_pot